Compensating means for gear tooth grinders



Nov. 12, 1935. I H, D TANNER 2,020,443

COMPENSATING MEANS FOR GEAR TOOTH GRINDERS Filed Feb. 10, 1934 4 Sheets-Sheet 1 INVENTOR H0. 72277127- ATTORNEY Nam 112, R935.

H. D. TANNER COMPENSATING MEANS FOR GEAR TOOTH GRINDERS Filed Feb. 10, 1934' 4 Sheets-Sheet 2 INVENTOR ATTORNEY Nov. 12, 1935.. D TANNER Y 2,,U2UA43 COMPENSATING MEANS FOR GEAR-TOOTH GRINDERS Filed Feb. 10, 1934 4 Sheets-Sheet 5 INVENTOR.

ATTORNEY NOV. 12, 1935. H, NNE 2,020,443

COMPENSATING MEANS FOR GEAR TOOTH GRINDERS Filed Feb. 10, 1934 4 Sheets-Sheet 4 i w l I I8 I l i l I I i 20 4'" w IQ. l/ F' 1 i S I INVENTOR ATroRNEY Patented Nov. 12, 1935 PATENT OFFICE CQMPENSATING MEANS FOR GEAR TOOTH GRINDERS Hubert D. Tanner, West Hartford, Conn, as-

, signor to Pratt & Whitney Company, Hartford,

Conn., a corporation of New Jersey Application February 10, 1934, Serial No. 710,662 3 Claims. (01. 51-123) This invention relates to gear tooth grinders of the type in which a gear blank is rolled past one or more abrasive wheels and particularly to means employed in that type of grinder for ef- 5 fecting the correct rolling action of a gear blank past the grinding wheel or wheels to generate tooth curves of the proper involute;

An object of the invention is to simplify and improve the means for obtaining the curve gen- 'erating motions of a gear blank being ground .by a master rack andmaster gear, these improved means enabling a single master rack to be used for grinding the sides of gear teeth having base or pitch circles of different diameters.

A feature of importance enabling the above mentioned object of the invention to be accomplished is that slight longitudinal movement of the master rack, actuated by adjustable linkage, takes place during the grinding operation, this movement being effected by and in timed relation to the motion of the slidable carriage supporting the master gear and the gear blank being finished.

Another object of the invention is to connect the slidable carriage mounting the master'gear and gear blank with the master rack by means of linkage adjustable in a manner to permit the master rack to be moved Variable distances for equal distances moved by the carriage. Primarily, the present invention is adapted for applicaton'to and constitutes an improvement of the gear grinder shown and described in my application for patent Serial No. 688,714 filed Sepe' tember 9, 1933. In such gear grinders the generating movements of the gear blank past the wheel are effected by simultaneously reciprocating and rotating the gear blank. These motions are produced by reciprocating a carriage rotatably 40 mounting a master gear and gear blank on an arborsupported between centers, the master gear on the arbor meshing with a normally fixed master rack. During the tooth curve generating movements of the gear blank'the master rack is maintained in fixed position andextending in a direction parallel to the direction of motion of the carriage. As a result of these motions the gear blank being finished must necessarily correspond in pitch diameter and number of teeth to the master gear. It is'to permit a single master gear to be used for finishing gears hav-' ing a range of different pitch diameters that the present construction has been developed.

A primary object of the invention therefore is to longitudinally .move the master rack during its engagement with the master gear and during the generating movements of the gear blank which take place during the grinding operation, these movements being adjustable in amount and preferably effected by linkage ac- 5 I tuated by and in timed relation to the reciprocatory movements of the carriage supporting the gear blank and master gear. It is a further object to provide means for supporting and moving the indexing slide inde- 10 pendently of the master rack and its actuating means so that the master gear and gear blank may be indexed during the longitudinal movements of the master rack.

With the above and other objects in view, my 15 invention consists in the features of construction and operation set forth in the following speci fication and illustrated in, the acompanying drawings. e

In the accompanying drawings annexed here- 20 to and forming a part of this specification, I have shown my invention embodied in a hydraulically operated involute gear tooth grinding machine, but it will be understood that the invention can be otherwise embodied and that 25 the drawings are not to be construed as defining or limiting the scope of the invention, the claims appended to this specification being relied upon for that purpose.

7 In the drawings: 30

Figure 1 is a front elevation of a portion of a gear tooth grinder showing the present invention applied thereto.

Fig. 2 is a front view of the mechanism forming the invention, parts being broken away to 35 more clearly show their construction and the carriage and master rack being indicated in two operative positions.

Fig. 3 is a view similar to Fig. 2, the parts being broken away to show the master rack, its 40 slide, the indexing member and its slide, these parts being shown in section.

Fig; 4 is a plan view of the parts shown in Figs. 2 and 3, partly in section; and

Fig. 5 is an end elevation of the complete mech- 45 anism forming the present invention, parts being shown on section line 5--5 of Fig. 1.

In the above mentioned drawings I have shown but one embodiment of the invention which is now deemed preferable, but it is to be understood that 50 changes and modifications may be made within the scope of the appended claims without departing from the spirit of the invention.

Briefly, and in its broadest aspect, the present invention includes the following parts in addition in a housing or slide I2.

housing for the master rack I and indexing rack to or materially different from those described in the gear grinder disclosed in my above referred to application: First, a slide in which the master rack is pivotally mounted at one end; second, a lever connected pivotally at its upper end to an end of the slide; third, a fulcrum member engaging opposite faces of the lever and held in fixed position relative to the machine; fourth, members engaging opposite faces of the lever and being attached to and movable with the carriage sup porting the master gear and the gear blank being finished; fifth, brackets supporting the lever engaging members, these brackets being adjustable respectively within a portion of the machine frame and carriage so that the oscillatory movements of the lever and reciprocatory movements of the rack may be varied; and sixth, operating connections mounted in the slide for effecting longitudinal movements of the indexing member during movements of the slide and master rack.

Referring more in detail to the figures of the drawings, the construction shown in the drawings is generally similar to that described and shown in my above referred to application in which a master rack is stationary during the grinding operations and engages a master gear corresponding exactly in pitch diameter and number of teeth to the gear being finished. In the above referred to application and in the present invention the rack is in mesh with the master gear during the rolling of the gear blank past the abrasive wheel or wheels, and is moved out of contact and back into a new position of the gear during indexing operations. In the mechanism disclosed in my pending application a number of different master racks are required, one for each pitch diameter and'number of teeth of the gears to be ground. It is obvious that the expense for large numbers of master racks and master gears and the resultant loss of time in setting up the machine with these different racks and gears in many instances is prohibitive, for which reason the present invention has been devised.

The means for mounting the master rack for longitudinal movement in addition to its pivotal -movement and for permitting the indexing rack to move with the master rack and have an indexing movement in addition thereto are contained This slide or enclosing 30 may be mounted upon horizontal ways' I3 on the upper end of the vertically movable bracket or frame portion I9 of the machine.

The gear being finished and the master gear I4 (one being directly behind the other) are mounted within a slidably mounted carriage 23 as in the copending application. By the connections presently to be described the transverse sliding movement of the carriage 23 causes sliding movement of the master rack III and parts associated therewith in the housing I2 variable distances.

The master rack I0 in the present invention, in-

stead of being fixed in position against longitudinal movement, is slidably mounted with its supporting slide I2. The ways I3 upon which the slide I2 reciprocates are parallel to the plane in which the axis of the gear being finished reciprocates. Itwill be understood that with the master rack I6 fixed in position during the rolling motion of the master gear I4 and gear being finished, the rolling motion would necessarily be equivalent to a rolling movement upon the pitch diameter of the master gear. However, should it be desired to finisha gear having a slightly different pitch diameter than the master gear, the rolling motion produced by the master gear for a gear of different pitch diameter would be incorrect. It is to correct this condition by compensating the effect of a master gear of one diameter to enable one master gear to simulate the rolling motion of 5 cylinders of different diameters that this mechanism has been devised.

In order to effect the sliding movement of the master rack III and its pivotally mounted arm II there is pivotally attached at one end of the slide I2 a downwardly extending arm or lever member I 5. The arm I I is pivoted to the housing or slide I2 by means of the transverse stud 9 so that the arm I I may oscillate freely and be moved longitudinally by movement of the slide I2. At the outer end of the slide I 2 the lever I5 is pivoted at 8. Oscillation of the lever I5 will therefore effect longitudinal movements of slide I2 and the master rack I0. I

Intermediate the length of this arm or lever I 5 are rollers I6 held in spaced apart position by a suitable strap member I1 and engaging opposite vertical surfaces of the lever I5. These rollers I6 are mounted on a. bracket I8 which may be secured adjustably in any vertical position to a portion of the fixed frame I9 of the machine. Adjacent the lower end of the lever I5 there is a pair of rollers 20 mounted on a suitable strap member 2I corresponding to the above described members, these rollers 20 being fastened with their strap member 2I to a bracket 22 secured vertically adjustably on the carriage 23 mounting the master gear I4 and the gear to be finished.

It will be seen from the above described construction that reciprocatory movement of the carriage 23,1aterally to'roll the master gear I I and the gear being finished (directly in rear of the master gear) past the abrasive wheel or wheels will oscillate the arm or lever I5 substantially about the intermediate rollers I6 as a fulcrum 0 point. This will give the slide I2 and the rack mounted thereon a longitudinal reciprocatory' movement in a direction parallel to that of the carriage 23, the movement of the rack I0 being always opposite that in which the carriage 23 5 moves. The distance moved by the master rack I II for any predetermined movement of the carriage 23 may be adjusted by varying the positions of the. brackets I8 and 22 supporting the 'pairs of rollers I6' and 20 so that greater or less their brackets the compensation effected by movement of the rack I0 may be sufiicient to vary the rolling effect imparted to the master gear and gear being finished to reproduce the rolling motion of pitch cylinders of varying diameters. The slide 23 supporting the master gear and gear being finished is reciprocated in the same manner as in the above-referred to application. I

In order to index the master gear and gear being finished an indexing rack 30 or slide having 05 spaced groups of teeth as in the above-mentioned application may be provided. As the master rack I0 is given a sliding movement in the present case whereas in my copending application it is fixed, some means must be provided to support and longitudinally move the indexing slide to effect indexing of the master gear I I and the gear being finished which also will permit sliding movement with the master rack during the grinding operation. For that purpose one end 01' the indexing slide 30 is provided with a member 3| having rack teeth extending parallel thereto and engaged by a segmental gear 32 mounted on a short transverse shaft 33. l The shaft 33 for the and meshes with a rack 38 formed on the upper end of the operating piston 33 for the indexing motion. Movements of this piston or motor 39 will rotate the gear 31 and shaft 36, which, throughthe bevel and spur gear segments 34 and 32 will reciprocate the indexing slide 30.

By means of the splined shaft 36 the mechanism for operating the indexing slide may reciprocate with the slide [2 in which it is mounted. The rack 38 and its meshing gear 3'! may be mounted in a bracket 43 fixed to a portion of the frame [6 of the machine. I i

The means for operating the indexing rack 30 at its proper point during the cycle of operation of the machine and the means for effecting the pivotal movements ofthe master rack 10 into and out of mesh with the master gear I 4 are not deemed necessary tobe described. The construction and operation of these actuating means are or may be in every way similar to those described in the above-mentioned copending application.

What I claim is:

1. In a machine for grinding gear teeth, in

combination, a base, a slidably mounted carriage thereon, a master gear supported on said carriage, a master rack supported on said base for longitudinal movement in a direction parallel to the direction of movement of said carriage and meshing with said master gear so that reciprocatory movements of said carriage will effect a rolling motion of said master gear, means to support a work blank coaxially with said master gear, and an arm pivotally mounted at one end of said master rack and adjustably connected pivotally to said carriage and base, whereby reciprocatory movements of said carriage will effect variable longitudinal movements of said rack.

2. In a machine for grinding gear teeth, in combination, a base, a slidably mounted carriage thereon, a master gear supported on said carriage, a master rack supported on said base for longitudinal movement in a direction parallel to the direction of movement of said carriage and meshing with said master gear so that reciprocatory movements of said carriage will effect a rolling motion of said master gear, means I to support a work blank coaxially with said master gear, an arm pivotally mounted on and depending from said master rack, said arm being pivotally connected adjustably to said carriage andbase, whereby movement of said carriage will effect longitudinal movement of said rack relative to said base, and means to adjust the pivotal connections of said arm with said carriage and base to vary the length of movement of said rack for predetermined movements of said carriage.

3. In a machine for grinding gear teeth, in

thereon, a master gear mounted on said carriage, a'master rack meshing with said master gear so that reciprocatory movements of said carriage will effect a rolling motion of said master gear, means to support a work blank coaxially with said master gear, a support for said master rack permitting slidable movement longitudinally thereof relative to the base, and an adjustable link pivotally connected to said master rack and adjustably connected to said base and carriage, straps on said carriage and base having rollers thereon engaging opposite faces of said arm, whereby movement of said carriage will effect predetermined different longitudinal movements of said rack.

HUBERT D. TANNER. 

